/* -*-mode:java; c-basic-offset:2; -*- */
/*
 Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

 1. Redistributions of source code must retain the above copyright notice,
 this list of conditions and the following disclaimer.

 2. Redistributions in binary form must reproduce the above copyright 
 notice, this list of conditions and the following disclaimer in 
 the documentation and/or other materials provided with the distribution.

 3. The names of the authors may not be used to endorse or promote products
 derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
 INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * This program is based on zlib-1.1.3, so all credit should go authors
 * Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
 * and contributors of zlib.
 */

package com.jcraft.jzlib;

final class InfCodes {

	static final private int[] inflate_mask = { 0x00000000, 0x00000001,
			0x00000003, 0x00000007, 0x0000000f, 0x0000001f, 0x0000003f,
			0x0000007f, 0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
			0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff };

	static final private int Z_OK = 0;
	static final private int Z_STREAM_END = 1;
	static final private int Z_NEED_DICT = 2;
	static final private int Z_ERRNO = -1;
	static final private int Z_STREAM_ERROR = -2;
	static final private int Z_DATA_ERROR = -3;
	static final private int Z_MEM_ERROR = -4;
	static final private int Z_BUF_ERROR = -5;
	static final private int Z_VERSION_ERROR = -6;

	// waiting for "i:"=input,
	// "o:"=output,
	// "x:"=nothing
	static final private int START = 0; // x: set up for LEN
	static final private int LEN = 1; // i: get length/literal/eob next
	static final private int LENEXT = 2; // i: getting length extra (have base)
	static final private int DIST = 3; // i: get distance next
	static final private int DISTEXT = 4;// i: getting distance extra
	static final private int COPY = 5; // o: copying bytes in window, waiting
										// for space
	static final private int LIT = 6; // o: got literal, waiting for output
										// space
	static final private int WASH = 7; // o: got eob, possibly still output
										// waiting
	static final private int END = 8; // x: got eob and all data flushed
	static final private int BADCODE = 9;// x: got error

	int mode; // current inflate_codes mode

	// mode dependent information
	int len;

	int[] tree; // pointer into tree
	int tree_index = 0;
	int need; // bits needed

	int lit;

	// if EXT or COPY, where and how much
	int get; // bits to get for extra
	int dist; // distance back to copy from

	byte lbits; // ltree bits decoded per branch
	byte dbits; // dtree bits decoder per branch
	int[] ltree; // literal/length/eob tree
	int ltree_index; // literal/length/eob tree
	int[] dtree; // distance tree
	int dtree_index; // distance tree

	InfCodes() {
	}

	void free(ZStream z) {
		// ZFREE(z, c);
	}

	int inflate_fast(int bl, int bd, int[] tl, int tl_index, int[] td,
			int td_index, InfBlocks s, ZStream z) {
		int t; // temporary pointer
		int[] tp; // temporary pointer
		int tp_index; // temporary pointer
		int e; // extra bits or operation
		int b; // bit buffer
		int k; // bits in bit buffer
		int p; // input data pointer
		int n; // bytes available there
		int q; // output window write pointer
		int m; // bytes to end of window or read pointer
		int ml; // mask for literal/length tree
		int md; // mask for distance tree
		int c; // bytes to copy
		int d; // distance back to copy from
		int r; // copy source pointer

		int tp_index_t_3; // (tp_index+t)*3

		// load input, output, bit values
		p = z.next_in_index;
		n = z.avail_in;
		b = s.bitb;
		k = s.bitk;
		q = s.write;
		m = q < s.read ? s.read - q - 1 : s.end - q;

		// initialize masks
		ml = inflate_mask[bl];
		md = inflate_mask[bd];

		// do until not enough input or output space for fast loop
		do { // assume called with m >= 258 && n >= 10
			// get literal/length code
			while (k < (20)) { // max bits for literal/length code
				n--;
				b |= (z.next_in[p++] & 0xff) << k;
				k += 8;
			}

			t = b & ml;
			tp = tl;
			tp_index = tl_index;
			tp_index_t_3 = (tp_index + t) * 3;
			if ((e = tp[tp_index_t_3]) == 0) {
				b >>= (tp[tp_index_t_3 + 1]);
				k -= (tp[tp_index_t_3 + 1]);

				s.window[q++] = (byte) tp[tp_index_t_3 + 2];
				m--;
				continue;
			}
			do {

				b >>= (tp[tp_index_t_3 + 1]);
				k -= (tp[tp_index_t_3 + 1]);

				if ((e & 16) != 0) {
					e &= 15;
					c = tp[tp_index_t_3 + 2] + (b & inflate_mask[e]);

					b >>= e;
					k -= e;

					// decode distance base of block to copy
					while (k < (15)) { // max bits for distance code
						n--;
						b |= (z.next_in[p++] & 0xff) << k;
						k += 8;
					}

					t = b & md;
					tp = td;
					tp_index = td_index;
					tp_index_t_3 = (tp_index + t) * 3;
					e = tp[tp_index_t_3];

					do {

						b >>= (tp[tp_index_t_3 + 1]);
						k -= (tp[tp_index_t_3 + 1]);

						if ((e & 16) != 0) {
							// get extra bits to add to distance base
							e &= 15;
							while (k < (e)) { // get extra bits (up to 13)
								n--;
								b |= (z.next_in[p++] & 0xff) << k;
								k += 8;
							}

							d = tp[tp_index_t_3 + 2] + (b & inflate_mask[e]);

							b >>= (e);
							k -= (e);

							// do the copy
							m -= c;
							if (q >= d) { // offset before dest
								// just copy
								r = q - d;
								if (q - r > 0 && 2 > (q - r)) {
									s.window[q++] = s.window[r++]; // minimum
																	// count is
																	// three,
									s.window[q++] = s.window[r++]; // so unroll
																	// loop a
																	// little
									c -= 2;
								} else {
									System.arraycopy(s.window, r, s.window, q,
											2);
									q += 2;
									r += 2;
									c -= 2;
								}
							} else { // else offset after destination
								r = q - d;
								do {
									r += s.end; // force pointer in window
								} while (r < 0); // covers invalid distances
								e = s.end - r;
								if (c > e) { // if source crosses,
									c -= e; // wrapped copy
									if (q - r > 0 && e > (q - r)) {
										do {
											s.window[q++] = s.window[r++];
										} while (--e != 0);
									} else {
										System.arraycopy(s.window, r, s.window,
												q, e);
										q += e;
										r += e;
										e = 0;
									}
									r = 0; // copy rest from start of window
								}

							}

							// copy all or what's left
							if (q - r > 0 && c > (q - r)) {
								do {
									s.window[q++] = s.window[r++];
								} while (--c != 0);
							} else {
								System.arraycopy(s.window, r, s.window, q, c);
								q += c;
								r += c;
								c = 0;
							}
							break;
						} else if ((e & 64) == 0) {
							t += tp[tp_index_t_3 + 2];
							t += (b & inflate_mask[e]);
							tp_index_t_3 = (tp_index + t) * 3;
							e = tp[tp_index_t_3];
						} else {
							z.msg = "invalid distance code";

							c = z.avail_in - n;
							c = (k >> 3) < c ? k >> 3 : c;
							n += c;
							p -= c;
							k -= c << 3;

							s.bitb = b;
							s.bitk = k;
							z.avail_in = n;
							z.total_in += p - z.next_in_index;
							z.next_in_index = p;
							s.write = q;

							return Z_DATA_ERROR;
						}
					} while (true);
					break;
				}

				if ((e & 64) == 0) {
					t += tp[tp_index_t_3 + 2];
					t += (b & inflate_mask[e]);
					tp_index_t_3 = (tp_index + t) * 3;
					if ((e = tp[tp_index_t_3]) == 0) {

						b >>= (tp[tp_index_t_3 + 1]);
						k -= (tp[tp_index_t_3 + 1]);

						s.window[q++] = (byte) tp[tp_index_t_3 + 2];
						m--;
						break;
					}
				} else if ((e & 32) != 0) {

					c = z.avail_in - n;
					c = (k >> 3) < c ? k >> 3 : c;
					n += c;
					p -= c;
					k -= c << 3;

					s.bitb = b;
					s.bitk = k;
					z.avail_in = n;
					z.total_in += p - z.next_in_index;
					z.next_in_index = p;
					s.write = q;

					return Z_STREAM_END;
				} else {
					z.msg = "invalid literal/length code";

					c = z.avail_in - n;
					c = (k >> 3) < c ? k >> 3 : c;
					n += c;
					p -= c;
					k -= c << 3;

					s.bitb = b;
					s.bitk = k;
					z.avail_in = n;
					z.total_in += p - z.next_in_index;
					z.next_in_index = p;
					s.write = q;

					return Z_DATA_ERROR;
				}
			} while (true);
		} while (m >= 258 && n >= 10);

		// not enough input or output--restore pointers and return
		c = z.avail_in - n;
		c = (k >> 3) < c ? k >> 3 : c;
		n += c;
		p -= c;
		k -= c << 3;

		s.bitb = b;
		s.bitk = k;
		z.avail_in = n;
		z.total_in += p - z.next_in_index;
		z.next_in_index = p;
		s.write = q;

		return Z_OK;
	}

	void init(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index,
			ZStream z) {
		mode = START;
		lbits = (byte) bl;
		dbits = (byte) bd;
		ltree = tl;
		ltree_index = tl_index;
		dtree = td;
		dtree_index = td_index;
		tree = null;
	}

	// Called with number of bytes left to write in window at least 258
	// (the maximum string length) and number of input bytes available
	// at least ten. The ten bytes are six bytes for the longest length/
	// distance pair plus four bytes for overloading the bit buffer.

	int proc(InfBlocks s, ZStream z, int r) {
		int j; // temporary storage
		int[] t; // temporary pointer
		int tindex; // temporary pointer
		int e; // extra bits or operation
		int b = 0; // bit buffer
		int k = 0; // bits in bit buffer
		int p = 0; // input data pointer
		int n; // bytes available there
		int q; // output window write pointer
		int m; // bytes to end of window or read pointer
		int f; // pointer to copy strings from

		// copy input/output information to locals (UPDATE macro restores)
		p = z.next_in_index;
		n = z.avail_in;
		b = s.bitb;
		k = s.bitk;
		q = s.write;
		m = q < s.read ? s.read - q - 1 : s.end - q;

		// process input and output based on current state
		while (true) {
			switch (mode) {
			// waiting for "i:"=input, "o:"=output, "x:"=nothing
			case START: // x: set up for LEN
				if (m >= 258 && n >= 10) {

					s.bitb = b;
					s.bitk = k;
					z.avail_in = n;
					z.total_in += p - z.next_in_index;
					z.next_in_index = p;
					s.write = q;
					r = inflate_fast(lbits, dbits, ltree, ltree_index, dtree,
							dtree_index, s, z);

					p = z.next_in_index;
					n = z.avail_in;
					b = s.bitb;
					k = s.bitk;
					q = s.write;
					m = q < s.read ? s.read - q - 1 : s.end - q;

					if (r != Z_OK) {
						mode = r == Z_STREAM_END ? WASH : BADCODE;
						break;
					}
				}
				need = lbits;
				tree = ltree;
				tree_index = ltree_index;

				mode = LEN;
			case LEN: // i: get length/literal/eob next
				j = need;

				while (k < (j)) {
					if (n != 0)
						r = Z_OK;
					else {

						s.bitb = b;
						s.bitk = k;
						z.avail_in = n;
						z.total_in += p - z.next_in_index;
						z.next_in_index = p;
						s.write = q;
						return s.inflate_flush(z, r);
					}
					n--;
					b |= (z.next_in[p++] & 0xff) << k;
					k += 8;
				}

				tindex = (tree_index + (b & inflate_mask[j])) * 3;

				b >>>= (tree[tindex + 1]);
				k -= (tree[tindex + 1]);

				e = tree[tindex];

				if (e == 0) { // literal
					lit = tree[tindex + 2];
					mode = LIT;
					break;
				}
				if ((e & 16) != 0) { // length
					get = e & 15;
					len = tree[tindex + 2];
					mode = LENEXT;
					break;
				}
				if ((e & 64) == 0) { // next table
					need = e;
					tree_index = tindex / 3 + tree[tindex + 2];
					break;
				}
				if ((e & 32) != 0) { // end of block
					mode = WASH;
					break;
				}
				mode = BADCODE; // invalid code
				z.msg = "invalid literal/length code";
				r = Z_DATA_ERROR;

				s.bitb = b;
				s.bitk = k;
				z.avail_in = n;
				z.total_in += p - z.next_in_index;
				z.next_in_index = p;
				s.write = q;
				return s.inflate_flush(z, r);

			case LENEXT: // i: getting length extra (have base)
				j = get;

				while (k < (j)) {
					if (n != 0)
						r = Z_OK;
					else {

						s.bitb = b;
						s.bitk = k;
						z.avail_in = n;
						z.total_in += p - z.next_in_index;
						z.next_in_index = p;
						s.write = q;
						return s.inflate_flush(z, r);
					}
					n--;
					b |= (z.next_in[p++] & 0xff) << k;
					k += 8;
				}

				len += (b & inflate_mask[j]);

				b >>= j;
				k -= j;

				need = dbits;
				tree = dtree;
				tree_index = dtree_index;
				mode = DIST;
			case DIST: // i: get distance next
				j = need;

				while (k < (j)) {
					if (n != 0)
						r = Z_OK;
					else {

						s.bitb = b;
						s.bitk = k;
						z.avail_in = n;
						z.total_in += p - z.next_in_index;
						z.next_in_index = p;
						s.write = q;
						return s.inflate_flush(z, r);
					}
					n--;
					b |= (z.next_in[p++] & 0xff) << k;
					k += 8;
				}

				tindex = (tree_index + (b & inflate_mask[j])) * 3;

				b >>= tree[tindex + 1];
				k -= tree[tindex + 1];

				e = (tree[tindex]);
				if ((e & 16) != 0) { // distance
					get = e & 15;
					dist = tree[tindex + 2];
					mode = DISTEXT;
					break;
				}
				if ((e & 64) == 0) { // next table
					need = e;
					tree_index = tindex / 3 + tree[tindex + 2];
					break;
				}
				mode = BADCODE; // invalid code
				z.msg = "invalid distance code";
				r = Z_DATA_ERROR;

				s.bitb = b;
				s.bitk = k;
				z.avail_in = n;
				z.total_in += p - z.next_in_index;
				z.next_in_index = p;
				s.write = q;
				return s.inflate_flush(z, r);

			case DISTEXT: // i: getting distance extra
				j = get;

				while (k < (j)) {
					if (n != 0)
						r = Z_OK;
					else {

						s.bitb = b;
						s.bitk = k;
						z.avail_in = n;
						z.total_in += p - z.next_in_index;
						z.next_in_index = p;
						s.write = q;
						return s.inflate_flush(z, r);
					}
					n--;
					b |= (z.next_in[p++] & 0xff) << k;
					k += 8;
				}

				dist += (b & inflate_mask[j]);

				b >>= j;
				k -= j;

				mode = COPY;
			case COPY: // o: copying bytes in window, waiting for space
				f = q - dist;
				while (f < 0) { // modulo window size-"while" instead
					f += s.end; // of "if" handles invalid distances
				}
				while (len != 0) {

					if (m == 0) {
						if (q == s.end && s.read != 0) {
							q = 0;
							m = q < s.read ? s.read - q - 1 : s.end - q;
						}
						if (m == 0) {
							s.write = q;
							r = s.inflate_flush(z, r);
							q = s.write;
							m = q < s.read ? s.read - q - 1 : s.end - q;

							if (q == s.end && s.read != 0) {
								q = 0;
								m = q < s.read ? s.read - q - 1 : s.end - q;
							}

							if (m == 0) {
								s.bitb = b;
								s.bitk = k;
								z.avail_in = n;
								z.total_in += p - z.next_in_index;
								z.next_in_index = p;
								s.write = q;
								return s.inflate_flush(z, r);
							}
						}
					}

					s.window[q++] = s.window[f++];
					m--;

					if (f == s.end)
						f = 0;
					len--;
				}
				mode = START;
				break;
			case LIT: // o: got literal, waiting for output space
				if (m == 0) {
					if (q == s.end && s.read != 0) {
						q = 0;
						m = q < s.read ? s.read - q - 1 : s.end - q;
					}
					if (m == 0) {
						s.write = q;
						r = s.inflate_flush(z, r);
						q = s.write;
						m = q < s.read ? s.read - q - 1 : s.end - q;

						if (q == s.end && s.read != 0) {
							q = 0;
							m = q < s.read ? s.read - q - 1 : s.end - q;
						}
						if (m == 0) {
							s.bitb = b;
							s.bitk = k;
							z.avail_in = n;
							z.total_in += p - z.next_in_index;
							z.next_in_index = p;
							s.write = q;
							return s.inflate_flush(z, r);
						}
					}
				}
				r = Z_OK;

				s.window[q++] = (byte) lit;
				m--;

				mode = START;
				break;
			case WASH: // o: got eob, possibly more output
				if (k > 7) { // return unused byte, if any
					k -= 8;
					n++;
					p--; // can always return one
				}

				s.write = q;
				r = s.inflate_flush(z, r);
				q = s.write;
				m = q < s.read ? s.read - q - 1 : s.end - q;

				if (s.read != s.write) {
					s.bitb = b;
					s.bitk = k;
					z.avail_in = n;
					z.total_in += p - z.next_in_index;
					z.next_in_index = p;
					s.write = q;
					return s.inflate_flush(z, r);
				}
				mode = END;
			case END:
				r = Z_STREAM_END;
				s.bitb = b;
				s.bitk = k;
				z.avail_in = n;
				z.total_in += p - z.next_in_index;
				z.next_in_index = p;
				s.write = q;
				return s.inflate_flush(z, r);

			case BADCODE: // x: got error

				r = Z_DATA_ERROR;

				s.bitb = b;
				s.bitk = k;
				z.avail_in = n;
				z.total_in += p - z.next_in_index;
				z.next_in_index = p;
				s.write = q;
				return s.inflate_flush(z, r);

			default:
				r = Z_STREAM_ERROR;

				s.bitb = b;
				s.bitk = k;
				z.avail_in = n;
				z.total_in += p - z.next_in_index;
				z.next_in_index = p;
				s.write = q;
				return s.inflate_flush(z, r);
			}
		}
	}
}
